At the present time, the most commonly used flow line weighing material comprises an inclined sensing plate carried on the end of a pivoted arm which is coupled to a linear displacement transducer, and which moves in a lateral direction against a spring due to the horizontal component of force of the material impinging upon the sloping face. The linear displacement transducer (load cell) provides a read-out which is a function of the force against the plate.
There are some problems which are encountered however and which not only cause the product to be expensive but also to have accuracy which can be doubted in certain instances.
These difficulties include the lever arm effect, wherein an impingement against a portion of the inclined plate more removed from its support can give a different reading from an impingement on another portion which is closer to the support. Furthermore, the mounting is essentially an expensive arrangement requiring transfer of movement and force from the projecting arm which carries a plate to the inner arm within a cabinet which co-operates with the linear displacement transducer. The moving parts are critical and must be maintained in good condition so that there is no loss due to seized or partly seized parts. Because of the existence of moving parts reliability is not as high as with the arrangement to be described in this specification. The provision of a cabinet to one side of the plate interferes with available space as well as adding to cost.